This tech demo is created by Art by Rens and according to the author, it is possible â with additional optimizations â to run it in 4K on a single NVIDIA GTX1080Ti. And while there are no human characters, no wind effects, no physics or environmental interactions, this tech demo looks unbelievably beautiful.

it's actually not an easy thing to do. All you see is scanned from photos (probably thousands of them) put into a Photoscan (app) converted into a 3D model, then compressed and exported to UE4 where he made everything else, including the shadow manipulation from taken photos. It's very complicated and long process.
In the end, what you need to remember: it's all 3D...running live...Although, Vanishing of Ethan Carter is the game that used the same process years ago..._________________-~ Trolling your forums since 1999 ~-